This is a known microsoft issue and normally happens when you turn your computer on, login and opening Outlook too quickly. This can cause the error and doesn't open correctly.
STEPS TO FOLLOW
1. Restart your PC and login.
2. Wait a few minutes before opening Outlook. (Maybe more minutes this depends on how quick your PC is).
3. Open outlook and all should be normal and working correctly.
If above solution doesn't work try waiting longer then the above suggestion it may take up to 10 min if not longer.
While waiting please go to the Vine and check out our other solution articles.